More than 1,700 Ukrainian fighters have surrendered to Russian forces after holding out for weeks inside the Azovstal steelworks at the strategic Ukrainian port city of Mariupol.

Located on the Sea of Azov, it is a key prize for Russia in its bid to connect the annexed Crimea peninsula to the west with territory held by pro-Russian rebels in the east.

Here are the key developments in the battle for Mariupol, which had a population of 441,000 before Russian invaded Ukraine on 24 February.

Pounded and encircled
On 2 March, Moscow's artillery begins pounding Mariupol.

The mayor accuses Russian forces and pro-Russian fighters of seeking to "impose a blockade" by cutting off food supplies and vital infrastructure, including water, electricity and heating.

Aerial view of damaged buildings in Mariupol and the Azovstal steel plant in the background

Maternity ward bombed
On 9 March, Russia targets a building housing a maternity ward and paediatric hospital in Mariupol, killing three people, including a young girl.

Ukraine and the European Union accuse Russia of a war crime. Russia claims the building is sheltering Ukrainian nationalists and that a heavily pregnant woman photographed being rescued is an actress.

First evacuations
Mid-March sees the start of the evacuation of thousands of civilians from the city through a humanitarian corridor.

Earlier evacuation attempts had collapsed with both sides accusing the other of failing to halt fire.

Theatre destroyed
On 16 March, Russian air strikes raze a theatre sheltering hundreds of people, mostly women and children. It takes days to reach survivors trapped in an underground shelter.

Ukrainian authorities estimate some 300 people were killed.

Moscow denies the attack, blaming Ukraine's far-right Azov battalion, which is based in the city.

Soldiers inside Mariupol's destroyed theatre

Hellish battle to survive
On 21 March, Kyiv rejects a first Russian ultimatum to Ukrainian forces in the city to surrender.

Civilians who manage to escape in their own vehicles describe apocalyptic scenes of streets riddled with dead bodies and a hellish struggle to survive starvation, thirst and cold amid relentless Russian bombardments.

Last battle
On 4 April, Mariupol's mayor says the city has been 90% destroyed.

A week later, Ukrainian forces say they are preparing for a "last battle" at the sprawling Azovstal steelworks, the last pocket of resistance to Russian control of the city.

Over the following week, Russia issues a string of ultimatums to the troops there to give themselves up but they refuse.

Regional authorities say the death toll in the city could exceed 20,000 people.

One of the last fighters in Azovstal

Mariupol 'liberated'
On 21 April, Russian President Vladimir Putin declares the "liberation" of Mariupol to be a "success."

He orders the Russian military to refrain from storming the Azovstal plant, telling them to besiege it instead, "so that not even a fly can escape".

Women, children rescued
On 7 May, Ukraine's government announces that all women, children and the elderly sheltering in the plant have been evacuated, amounting to nearly 500 people.

On 9 May, pro-Russian forces in Mariupol hold a parade through the ruined streets to commemorate the Soviet victory over Nazi Germany during World War II.

Five days later, a Ukrainian group, Kalush Orchestra, wins the Eurovision song contest and uses the platform to appeal for help for the soldiers holed up inside Azovstal.

Mariupol evacuees are taken to safety

On 17 May, a first group of more than 260 Ukrainian soldiers surrenders to Russian forces.

They are taken captive by Russian forces, with the wounded admitted to a hospital in a Russian-controlled part of the Donetsk region.

By today, 1,730 Ukrainian fighters have surrendered, according to Moscow. Their fate is uncertain.

Ukraine wants to swap them for Russian prisoners of war but a pro-Russian separatist leader suggests some will be put on trial.